1. Field of the Invention
Embodiments of the present invention relate to a photosensitive resin, a photoresist composition having the photosensitive resin, and a method of forming a photoresist pattern using the photoresist composition.
2. Description of the Related Art
Recently, as information technology such as a computer is spreaded rapidly, semiconductor devices have been developed swiftly. Semiconductor devices having high integration degree and rapid response speed are desired in functional aspects. Hence, the technology of manufacturing the semiconductor devices has been developed to improve integration degree, reliability and response speed of the semiconductor devices. Particularly, the requirements for a microprocessing technology such as a photolithography process have become strict.
In a semiconductor manufacturing process, a photoresist composition is used in the photolithography process. Solubility of the photoresist composition varies with respect to a developing solution in accordance with exposure to light. Thus, a desired pattern is obtained by coating the photoresist composition to form a photoresist film, selectively exposing the photoresist film to light and developing the exposed portion of the photoresist film.
In the semiconductor device having a design rule of about 240 nm, the roughness deviation of the photoresist pattern is about 20 nm, so that a line width roughness of about 16 percent exists. However, as the design rule of the semiconductor device has shrunk below about 90 nm, the roughness width of the photoresist pattern has increased to 22 percent, particularly in the semiconductor device having a design rule of below about 70 nm, the line width roughness has increased to over 29 percent.
Until recently, for improving the profile of the photoresist pattern, a molecular weight of a photosensitive resin or a kind of a blocking group included in the photoresist composition have been mainly changed. However, when these photoresist compositions are used, occasional loss of the photoresist pattern increases a number of developing processes or the physical properties of the photosensitive resin are deteriorated. This is because the size of the photosensitive resin is not considered in improving characteristics of the photoresist composition.
Therefore, a need still exists for a photoresist composition capable of forming a photoresist film having a uniform profile, for preventing the photoresist pattern from swelling in a developing process and a cleaning process, and for providing good reproducibility and high resolution.